July 17, 2017

By way of Scientific American, here’s a bit of clarity from Monica Reinagel about the issue of sulfites in both red and white wine and what relationship it has to wine headaches:

Myth #1: Organic or bio-dynamic wines are sulfite free.

In order to be certified organic, a wine must not contain added sulfites. However, sulfites are produced naturally during the fermentation process as a by-product of yeast metabolism. Even though no sulfites are added, organic wine may contain between 10-40 ppm sulfites.

You may also see wines labeled as being made from organic grapes, which is not the same as organic wine. Wine made from organic grapes may contain up to 100 ppm sulfites.

If you do get a hold of wine made without sulfites, I don’t suggest keeping it in the cellar very long. Wine made without sulfites—especially white wine — is much more prone to oxidation and spoilage.

Myth #2: Red wine is higher in sulfites than white wine

Ironically, the exact opposite is likely to be true. Red wines tend to be higher in tannins than white wines. Tannins are polyphenols found in the skins, seeds, and stems of the grapes. They also act as antioxidants and preservatives so less sulfite is needed.

In fact, while European regulations allow up to 210 ppm sulfites in white wine, the limit for red wine is only 160 ppm.

Other factors that affect how much sulfite is needed are the residual sugar and the acidity of the wine. Dryer wines with more acid will tend to be lower in sulfites. Sweet wines and dessert wines, on the other hand, tend to be quite high in sulfites.

Myth #3: Sulfites in wine cause headaches

The so-called “red wine headache” is definitely a real thing. But it’s probably not due to sulfites. For one thing, white wine is higher in sulfites than red wine but less likely to cause a headache. That suggests that it’s probably something else in red wine that’s responsible for the notorious red wine headache. Other candidates include histamines, tyramine, tannins, not to mention the alcohol itself!

June 17, 2017

Have you ever wondered what happens to a human body when it takes anabolic steroids? Well, Greg Foot is here to explain all the science you need to know about steroids and why people use them for muscle growth.

June 2, 2017

Get a whiff of this! James May delves in to the mechanics of deodorant.

Did you know that our sweat doesn’t smell? Made up of various things like our diet and genetics, it actually does not pong. Rather it’s when your sweat mixes with the bacteria on your skin that it releases an odor that can sometimes clear a room. Your armpits and pubic areas contain thousands of hairs which then hold on to your sweat and bacteria.

Us humans aren’t alone in smelling, many animals have some serious BO too. It’s not such a bad thing for them, it helps them mark out territory, repelling enemies and, most importantly, attracting mates.

Deodorants work by killing the bacteria on your skin and they also work as an anti-perspirant by reducing the amount of sweat. No more BO!

April 22, 2017

One last, minor thing: Vanilla is a deeply rich flavor that has unfairly become shorthand for boring, basic, and sexually unadventurous. Merriam-Webster’s second definition includes the sad phrase “lacking distinction” to explain the term “vanilla.” I’m not arguing that we drop this secondary use of the word — we’re too far gone for that — but I do want to remind people that vanilla is actually an extraordinarily complex flavor. Chocolate is far more vanilla than vanilla.

Long-time readers know that very useful measures of both radioactivity and radiation dose rates are the Banana Equivalent Dose (BED), and a similar measure I think I invented (because no one else ever bothered) called the Banana Equivalent Radioactivity (BER). (The units here are explained in my old article “Understanding Radiation.”)

Bananas are useful for these measures because bananas concentrate potassium, and a certain amount of that potassium is ⁴⁰K, which is naturally radioactive. The superscript “40” there is the atomic number, or the number of protons in the nucleus, of that particular potassium (symbol K) isotope. Because of that potassium content, bananas are mildly radioactive: a medium banana at around 150g emits about 1 micro-Sievert per hour (1 µSv/hr) and contains about 15 Becquerel (15 Bq) of radioactive material.

(Why bananas? There are a lot of plant-based foods that concentrate potassium. It is, however, an essential rule of humor that bananas are the funniest fruit.)

Our radioactive boars are considered unfit at 600 Bq per kilogram. So, a tiny bit of arithmetic [(1000 g/kg)/150 g/banana × 15 Bq/banana] gives us 100 Bq/kg for bananas. All right, so this boar meat has 6 times as much radioactivity as a banana. Personally, this wouldn’t worry me.

So let’s turn to the radioactivity detected off the Oregon coast. This is 0.3 Bq per cubic meter. Conveniently — the joys of metric — one cubic meter of water is one metric tonne is 1000 liters is 1000 kilograms, so the radiation content here is .0003 Bq/kg.

15/0.0003 is 50,000. So, bananas have 50,000 times more radiation than the seawater being reported.

October 31, 2015

On a hot summer’s day, the cool, refreshing taste of cider is hard to beat. But what are the chemicals behind this flavour?

Before we look at the chemistry, let’s briefly discuss how cider is made. Obviously, it starts with the apples being picked from the tree. The type of apples is, of course, a major factor in the taste of the finished cider. Bittersweet cider apples are low on acidity, but high on tannins, whilst sharp apples are the opposite. Sweet apples, meanwhile, are low in both departments, whilst bittersharp apples are high in both.

Once the apples have been picked, they’re left to mature for a time before then being scratted, or ground down, into a pulp. The pulp produced by this process is known as pomace. This pomace is then pressed to squeeze out all of the juice, which is collected into either vats or casks. At this point, it is then slowly fermented, and yeasts convert the natural sugars in the apples into alcohol. These yeasts can be the natural yeasts present in the apples, or yeasts that are added specifically for fermentation.

After fermentation is complete, the cider will often be left to mature for several months. At this point, extra sugar is sometimes added to the cider to allow fermentation to continue, and produce a small amount of carbon dioxide to carbonate the cider. However, commercially carbonation is often primarily accomplished via direct injection of carbon dioxide. In the manufacture of some ciders, they may be blended with other, older ciders, to ensure consistency of taste or to alter the flavour.

October 16, 2015

The entire brain weighs three pounds (1.4 kg) and so is only a small percentage of an adult’s total body weight, typically 2%. But it consumes 20% of all the energy the body uses. Why? The perhaps oversimplified answer is that time is energy.

Neural communication is very rapid — it has to be — reaching speeds of over 300 miles per hour and with neurons communicating with one another hundreds of times per second. The voltage output of a single resting neuron is 70 millivolts, about the same as the line output of an iPod. If you could hook up a neuron to a pair of earbuds, you could actually hear its rhythmic output as a series of clicks.

[…]

Neurochemicals that control communication between neurons are manufactured in the brain itself. These include some relatively well-known ones such as serotonin, dopamine, oxytocin, and epinephrine, as well as acetylcholine, GABA, glutamate, and endocannabinoids. Chemicals are released in very specific locations and they act on specific synapses to change the flow of information in the brain. Manufacturing these chemicals, and dispersing them to regulate and modulate brain activity, requires energy — neurons are living cells with a metabolism, and they get that energy from glucose. No other tissue in the body relies solely on glucose for energy except the testes. (This is why men occasionally experience a battle for resources between their brains and their glands.)

August 23, 2015

Ice cream is a mainstay of summer – for many, a trip to the beach would be incomplete without one. Despite its seeming simplicity, ice cream is a prime example of some fairly complex chemistry. This graphic takes a look at some of the ingredients that go into ice cream, and the important role they play in creating the finished product. There’s a lot to talk about – whilst the graphic gives an overview, read on for some in-depth ice cream science!

Initially, it might be hard to believe that ice cream could be all that complicated. After all, it’s essentially composed of three basic ingredients: milk, cream, and sugar. How complex can the mixing of three ingredients really be? As it turns out, the answer is: very! Simply mixing the ingredients together, then freezing them, isn’t enough to make a good ice cream. To understand why this is, we’re going to need to talk about each of the component ingredients in turn, and what they bring to the table.

Ice cream is a type of emulsion, a combination of fat and water that usually wouldn’t mix together without separating. However, in an emulsion, the very small droplets of fat are dispersed through the water, avoiding this separation. The manner in which this is accomplished is a result of the chemical properties of molecules in the emulsion.

The fat droplets in ice cream come from the cream used to make it. Fats are largely composed of a class of molecules called triglycerides, with very small amounts (less than 2%) of other molecules such as phospholipids and diglycerides. The triglycerides are made up of a glycerol molecule combined with three fatty acid molecules, as shown in the graphic. The melting temperature of the fats used in ice cream is quite important, as fats that melt at temperatures that are too high give a waxy feel in the mouth, whilst it’s difficult to make stable ice cream with those that melt at too low a temperature. Luckily, dairy fat falls just in the right range! As it happens, you can also make ice cream with palm oil and coconut oil, as their melting temperatures are similar.

August 20, 2015

In Forbes, Henry I. Miller and Drew L. Kershen explain why they think organic farming is, as they term it, a “colossal hoax” that promises far more than it can possibly deliver:

Consumers of organic foods are getting both more and less than they bargained for. On both counts, it’s not good.

Many people who pay the huge premium — often more than 100% — for organic foods do so because they’re afraid of pesticides. If that’s their rationale, they misunderstand the nuances of organic agriculture. Although it’s true that synthetic chemical pesticides are generally prohibited, there is a lengthy list of exceptions listed in the Organic Foods Production Act, while most “natural” ones are permitted. However, “organic” pesticides can be toxic. As evolutionary biologist Christie Wilcox explained in a 2012 Scientific American article (“Are lower pesticide residues a good reason to buy organic? Probably not.”): “Organic pesticides pose the same health risks as non-organic ones.”

Another poorly recognized aspect of this issue is that the vast majority of pesticidal substances that we consume are in our diets “naturally” and are present in organic foods as well as non-organic ones. In a classic study, UC Berkeley biochemist Bruce Ames and his colleagues found that “99.99 percent (by weight) of the pesticides in the American diet are chemicals that plants produce to defend themselves.” Moreover, “natural and synthetic chemicals are equally likely to be positive in animal cancer tests.” Thus, consumers who buy organic to avoid pesticide exposure are focusing their attention on just one-hundredth of 1% of the pesticides they consume.

Some consumers think that the USDA National Organic Program (NOP) requires certified organic products to be free of ingredients from “GMOs,” organisms crafted with molecular techniques of genetic engineering. Wrong again. USDA does not require organic products to be GMO-free. (In any case, the methods used to create so-called GMOs are an extension, or refinement, of older techniques for genetic modification that have been used for a century or more.)

Today’s post looks at an aspect of chemistry we come across every day: alloys. Alloys make up parts of buildings, transport, coins, and plenty of other objects in our daily lives. But what are the different alloys we use made up of, and why do we use them instead of elemental metals? The graphic answers the first of these questions, and in the post we’ll try and answer the second.

First, a little on what alloys are, for anyone unfamiliar with the term. Alloys are a mixture of elements, where at least one of the elements is a metal. There are over 80 metals in the periodic table of elements, and we can mix selections of these different metals in varying proportions, sometimes with non-metals too, to create alloys. Note the use of the word mixture: in the vast majority of cases, alloys are simply intermixed elements, rather than elements that are chemically bonded together.

June 23, 2015

Fritz Haber is one of the most famous German scientists. His inventions made it possible to feed an ever growing human population and influence us till this day. But Fritz Haber had a dark side too: His research made the weaponization of gas and the increased production of explosives possible. Find out more about the life of Fritz Haber in our biography.